Cloud storage refers to providing online data storage services including database-like services, web-based storage services, network attached storage services, and synchronization services. Examples of database storage services include Amazon SimpleDB, Google App Engine and BigTable datastore, among others. Examples of web-based storage services include Amazon Simple Storage Service (Amazon S3) and Nirvanix SDN, among others. Examples of network attached storage services include MobileMe, iDisk and Nirvanix NAS, among others. Examples of synchronization services include Live Mesh, MobileMe push functions and Live Desktop component, among others.
Customers usually rent data capacity on demand over the Internet, or use local pools of inexpensive storage as a private utility, anywhere within their business. Cloud storage services are usually billed on a utility computing basis, e.g., per gigabyte per month. Cloud storage provides flexibility of storage capacity planning and reduces the storage management overhead by centralizing and outsourcing data storage administrative and infrastructure costs.
However, the benefits of cloud storage do come with some significant drawbacks. Business data are extremely critical to the operations of any business and need to be reliable, secure and available on demand. Even a minor security breach or black out in the data availability can have drastic consequences. Current Internet-based cloud storage implementations do not usually deploy security measures that are adequate to protect against even minor security breaches. Availability and reliability has also not been up to the standards of even small-to-medium size enterprises. Furthermore, cloud storage is not standards-based and businesses usually need to invest in application development in order to be able to use them. In particular, different cloud storage systems provide different interfaces and have different requirements for the data presentation and transfer. For example, Amazon S3 allows reading objects containing from 1 to 5 gigabytes of data each (extents), storing each object in a file and uploading (sending data from a local system to a remote system) only the entire file, whereas Nirvanix SDN allows writing to any extent but only downloading (receiving data to a local system from a remote system) the entire file. Continuous data replication between data stored in these two different cloud storage systems is currently unavailable.
A one time data migration process from Amazon S3 to Nirvanix SDN is described in http://www.nirvanix.com/s3migrationtool.aspx. It requires downloading and installing a specialized software, is cumbersome, inefficient for continuous data replication, not reliable or secure and therefore it is currently not used at least for business storage applications.
Accordingly, there is a need for a reliable and secure multi cloud data replication solution that is secure, inexpensive, easy to use and scalable without compromising performance.